... you quality,timely delivery; 3>Had been approved by ASTM. alloy seamless steel tube: Material: 12Cr1MoV, P22(10CrMo910), T91, P91, P9 ... (P11P12STFA22), 13CrMo44, Cr5Mo, 15CrMo, 25CrMo, 30CrMo, 40CrMo, and so on Standard: DIN17175-79, JISG3467-88, JISG3458-88, GB5310-95, GB9948-88 ...